Dietary patterns and breast cancer risk in the California Teachers Study cohort.

BACKGROUND: Evidence that diet is associated with breast cancer risk is inconsistent. Most studies have examined risks associated with specific foods and nutrients, rather than measures of overall diet. OBJECTIVE: This study aimed to evaluate dietary patterns and their relation to breast cancer risk in a large cohort of women. DESIGN: Data from 91,779 women in the California Teachers Study cohort were analyzed, including data from 4140 women with a diagnosis of invasive breast cancer made between 1995 and 2009. Five predominant dietary patterns were identified by using principal components factor analysis: a plant-based diet, high in fruit and vegetables; a high-protein, high-fat diet, high in meats, eggs, fried foods, and high-fat condiments; a high-carbohydrate diet, high in convenience foods, pasta, and bread products; an ethnic diet, high in legumes, soy-based foods, rice, and dark-green leafy vegetables; and a salad and wine diet, high in lettuce, fish, wine, low-fat salad dressing, and coffee and tea. RESULTS: The plant-based pattern was associated with a reduction in breast cancer risk (RR: 0.85; 95% CI: 0.76, 0.95 for the highest compared with the lowest consumption quintile; P-trend = 0.003); risk reduction was greater for estrogen receptor-negative progesterone receptor-negative (ER-PR-) tumors (RR: 0.66; 95% CI: 0.48, 0.91; P-trend = 0.03). The salad and wine pattern was associated with an increased risk of estrogen receptor-positive progesterone receptor-positive tumors (RR: 1.29; 95% CI: 1.12, 1.49); this effect was only slightly attenuated after adjustment for alcohol consumption. CONCLUSION: The finding that greater consumption of a plant-based dietary pattern is associated with a reduced breast cancer risk, particularly for ER-PR- tumors, offers a potential avenue for prevention.

Change in quality of life and immune markers after a stay at a raw vegan institute: a pilot study.

OBJECTIVE: The purpose of this study was to explore changes in quality of life (QOL), anxiety, stress, and immune markers after a stay at a raw vegan institute. DESIGN: Prospective observational study. SETTING: English-speaking attendees at Hippocrates Health Institute (Florida, US), a raw vegan institute, were recruited on arrival and typically stayed 1-3 weeks. MAIN OUTCOME MEASURES: Participants completed questionnaires assessing overall QOL (SF-36), dietary QOL (QOL related to dietary change), perceived stress (Perceived Stress Scale), anxiety, and depression (Hospital Anxiety and Depression Scale) upon arrival and 12 weeks later. C-reactive protein (CRP), lymphocytes, T cells, CD4 cells, CD8 cells, B cells, and NK cells were measured at baseline and 12 weeks in participants living in North America. RESULTS: Of 107 attendees eligible for the questionnaire study and 82 for the blood marker substudy, 51 and 38 participants, respectively, provided complete follow-up data. Overall QOL improved 11.5% (p=0.001), driven mostly by the mental component. Anxiety decreased 18.6% (p=0.009) and perceived stress decreased 16.4% (p<0.001). Participants' ratings of the food's taste were unchanged, but their ratings of how well they were taking care of themselves improved. CRP, lymphocytes, T cells, and B cells did not change significantly, but CD4, CD8, and NK cells decreased slightly. CONCLUSIONS: A stay at a raw vegan institute was associated with improved mental and emotional QOL. Studies are needed to determine the feasibility of conducting a clinical trial of the raw vegan diet among healthy people, and subsequently among patients with specific diseases.

Factors affecting adherence to a raw vegan diet.

The purpose of this study was to evaluate adherence and identify predictors of adherence to a raw vegan diet (i.e., uncooked plant foods) following a stay at a raw vegan institute. In this cohort study of guests at a raw vegan institute, subjects completed written questionnaires upon arrival and 12 weeks later. Of 107 eligible guests, 84 participated. Mean age was 54 years, 23 were male, and 73 white. Fifty-one completed the 12-week follow-up. Eight (16%) reported their diet to be 80% raw vegan at baseline and 14 (28%) at follow-up. Based on a raw vegan dietary adherence score (range 0-42) created for this study, mean adherence (SD) increased from 15.1 (5.4) to 17.0 (5.8) over 12 weeks (p=0.03). Baseline predictors of adherence included: education (beta=0.95), severity of disease (beta=0.98), and self-efficacy to adhere (beta=0.72). Future interventions that evaluate this diet should address self-efficacy, an important, potentially remediable predictor of adherence.

Adherence to a low-fat diet in men with prostate cancer.

OBJECTIVES: To evaluate, in a feasibility study, the adherence to a low-fat diet by men with prostate cancer. Evidence is growing that a low-fat diet affects the development and course of prostate cancer. To design preventive and therapeutic interventions, it is important to know whether men will adhere to these nutritional recommendations, particularly when motivated by the diagnosis of prostate cancer. METHODS: Men with elevated prostate-specific antigen levels, most of whom were recently treated for prostate cancer, were randomized to one of four dietary regimens for which they received nutritional counseling: a low-fat diet (15% fat or less) with supplements (vitamin E and selenium), a low-fat diet (15% fat or less) without the supplements, the supplements alone, and a control group. Adherence was evaluated by the change in weight, fat intake, free fatty acids, cholesterol, high-density and low-density lipoproteins, and triglycerides during a 12-month period. RESULTS: The mean age of the 48 participants was 66 years. For those counseled about a low-fat diet, the mean change in the percentage of energy (kilocalories) in the diet from fat was greater after 3 months (-8.6% versus +2.1%, P <0.001) and 12 months (-9.8% versus -1.6%, P = 0.001). Three months after starting the intervention, those randomized to low-fat dietary counseling had lost 2 kg, on average, compared with 0.8 kg lost by those who did not receive this counseling (P = 0.09). At 12 months, those receiving low-fat counseling had lost 2.8 kg, on average, compared with 0.5 kg gained among the other groups (P = 0.02). CONCLUSIONS: With appropriate counseling, men with prostate cancer can adhere to a low-fat dietary intervention for a 12-month period.

Raw versus cooked vegetables and cancer risk.

This review of the medical literature from 1994 to 2003 summarizes the relationship between raw and cooked vegetables and cancer risk and examines whether they may affect cancer risk differently. Twenty-eight studies examined the relationship between raw and cooked vegetables and risk for various cancers. Twenty-one studies assessed raw, but not cooked, vegetables and cancer risk. The majority of these assessed risk of oral, pharyngeal, laryngeal, esophageal, lung, gastric, and colorectal cancers. Most showed that vegetables, raw or cooked, were inversely related to these cancers. However, more consistent results were found for oral, pharyngeal, laryngeal, esophageal, and gastric cancers. Nine of the 11 studies of raw and cooked vegetables showed statistically significant inverse relationships of these cancers with raw vegetables, but only 4 with cooked vegetables. The few studies of breast, lung, and colorectal cancers also suggested an inverse relationship with both raw and cooked vegetables, but these results were less consistent. In the two studies of prostate cancer, there was no association with either raw or cooked vegetables. One of two bladder cancer studies found an inverse relationship with cooked, but not raw, vegetables. Possible mechanisms by which cooking affects the relationship between vegetables and cancer risk include changes in availability of some nutrients, destruction of digestive enzymes, and alteration of the structure and digestibility of food. Both raw and cooked vegetable consumption are inversely related to epithelial cancers, particularly those of the upper gastrointestinal tract, and possibly breast cancer; however, these relationships may be stronger for raw vegetables than cooked vegetables.